(a) Field of the Invention
The invention relates to an electrowetting pixel structure.
(b) Description of the Related Art
FIG. 1A and FIG. 1B show cross-sectional schematic diagrams illustrating a display unit 100 of a conventional electrowetting display. As shown in FIG. 1A and FIG. 1B, the display unit 100 includes a polar liquid 102, a black ink 104, and a hydrophobic dielectric layer 106. As shown in FIG. 1A, when no voltage is applied, the black ink 104 evenly covers an upper surface of the hydrophobic dielectric layer 106 and thus ambient light or a backlight is absorbed to show a dark state. On the contrary, as shown in FIG. 1B, when a voltage supplied by a voltage source 116 is applied to a transparent electrode 108, an interface between the hydrophobic dielectric layer 106 and the aqueous solution 102 is polarized to increase surface energy. In that case, the hydrophobic dielectric layer 106 becomes less hydrophobic to push the black ink 104 aside to the rib 112. At this time, ambient light is allowed to be reflected by the bottom substrate 114 or the backlight is allowed to pass through the bottom substrate 114 to form a bright state. Such design uses a transparent electrode (such as an indium tin oxide electrode) spreading on an entire surface to drive the black ink 104, and the to spread over the whole surface but, when the black ink 104. Hence, as the black ink 104 contracts on the hydrophobic dielectric layer 106, a delay in ink contraction often occurs and the black ink 104 tends to stay at a corner or an edge of each pixel, as shown in FIG. 1C. This results in a considerable decrease in the display quality and the response speed of an electrowetting display.